Impregnation, vapor phase and methanol as means of intensifying the softwood kraft pulping process

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Enqvist, Eric
dc.date.accessioned 2012-02-24T07:46:16Z
dc.date.available 2012-02-24T07:46:16Z
dc.date.issued 2006-10-27
dc.identifier.isbn 951-22-8407-3
dc.identifier.issn 1457-750X
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/2778
dc.description.abstract The objective of the research was to find ways to shorten the cooking time, i.e. intensify the kraft pulping process. The reason for undertaking such a study lies in the long standing trend of ever increasing reactor size in the kraft pulping industry. The huge digester size in use presently has lead to severe problems in understanding the behavior of the chip column inside the digester. An intensified process with a drastically shorter pulping time would give a more manageable process and greater freedom in reactor design. The study was performed using a new experimental digester giving a much greater control over temperatures than what can be achieved with other types of digesters. This enabled experiments that clarify the impact of impregnation, heat-up time, cooking temperature and cooking time to a greater degree than what has been possible earlier. The research on actual intensification centered on understanding the impact of impregnation and the impact of alcohols (methanol) on the overall rate of pulping. This research supports earlier research that shows how the cooking time can be shortened using alcohols as additives in pulping. It also supports results showing that a fast process can be achieved by using impregnation with high concentrations of cooking chemicals followed by a cooking stage performed with direct steam heating. The fact that the effects work in synergy so that the fastest pulping process identified was one that employed high concentration impregnation followed by heating using methanol steam is a new finding. The decrease in cooking time compared to a conventional liquid phase batch process without proper impregnation is close to 70%. The present research was aimed only at shortening the cooking time and does not address questions related to actual digester and process design and economical feasibility of the process. Especially the regeneration of cooking chemicals and methanol are an area that will need further study before such question can be addressed. en
dc.format.extent 139
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.ispartofseries Report / Helsinki University of Technology, Laboratory of Pulping Technology. Series A en
dc.relation.ispartofseries 30 en
dc.subject.other Paper technology en
dc.title Impregnation, vapor phase and methanol as means of intensifying the softwood kraft pulping process en
dc.type G4 Monografiaväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Forest Products Technology en
dc.contributor.department Puunjalostustekniikan osasto fi
dc.subject.keyword kraft pulping en
dc.subject.keyword organosolv en
dc.subject.keyword alcohol en
dc.subject.keyword methanol en
dc.subject.keyword softwood en
dc.subject.keyword vapor phase en
dc.subject.keyword rapid delignification en
dc.subject.keyword sulfatkok sv
dc.subject.keyword organosolv sv
dc.subject.keyword alkohol sv
dc.subject.keyword metanol sv
dc.subject.keyword barrträd sv
dc.subject.keyword ångfas sv
dc.subject.keyword snabb delignifiering sv
dc.identifier.urn urn:nbn:fi:tkk-008365
dc.type.dcmitype text en
dc.programme.major Chemical Pulping en
dc.type.ontasot Väitöskirja (monografia) fi
dc.type.ontasot Doctoral dissertation (monograph) en
dc.contributor.lab Laboratory of Chemical Pulping and Environmental Technology en
dc.contributor.lab Prosessiteollisuuden ympäristötekniikan laboratorio fi


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